Decembee 3, 1909] 



SCIENCE 



807 



traced back to a fundamental property of 

 protoplasm, and, like the capacity to vary, 

 this property becomes more and more limited 

 with advanced differentiation until, in the 

 highest types of animals, the power of re- 

 generation is much more reduced than in 

 lower forms. This power, he thinks, still re- 

 mains in the germ plasm which in higher 

 animals becomes more and more localized in 

 specific organs while in plants and in lower 

 animals it is still present in part, at least, in 

 all somatic cells, making them what Driesch 

 calls " equipotential." Not only in different 

 animal types does this somatic and germinal 

 distinction exist, but among the different 

 cells of the same individual as well, the dif- 

 ference being measured by their relative 

 power to regenerate, from which it follows 

 that " the regenerative power of a cell-type is 

 a criterion of its differentiation" (p. 44). 



The expression " struggle for existence," as 

 used in current theories, he regards as an 

 ■erroneous phrase for the description of nat- 

 ural phenomena. The conditions throughout 

 all nature, he thinks, indicate a " compro- 

 mise " of individuals bound by the funda- 

 mental law of altruism which is as strikingly 

 ■operative between varieties, species and races 

 as it is between the various organs, tissues and 

 cells of the individual. 



Manche Lebewesen stehen in so enger altruist- 

 ischer Beziehung zueinander, dass sie bei kiinst- 

 iicher Aufhebung derselben zu Grunde gehen. Bei 

 anderen ist dieser Verhiiltnis ein viel locheres, ja 

 viele Arten stehen so weit auseinander, dass die 

 altruistischen Beziehungen zwischen ihnen gar- 

 nicht niehr erkannt werden konnen. Man kann 

 miit Sicherheit behaupten, dass iiberall, wo diese 

 Beziehungen enge sind, eine Abhangigkeit in der 

 phylogenetischen Entwicklung bestanden hat. 

 ■Ganz besonders deutlich tritt das bei Anpassung 

 von Instinkten zweier Tiere in die Erscheinung, 

 z. B. bei der Symbiose des Einsiedlerkrebses und 

 der Aktinie, und man ersieht daraus, dass diese 

 liingst anerkannte und auch schon von Darwin 

 hervorgehobene Tatsache sich au3 den Ergchein- 

 ■ungen des Altruismus ausreichend erkliirt (p. 

 ■22.'5). 



Bearing the title it does, one naturally 

 looks under the heading " Epidemics " for 

 ■something more akin to pathology than the 



other chapters present. But a zoologist would 

 have little use for the medical information to 

 be gathered here. The term " epidemic " is 

 used in its broadest sense and not at all with 

 the usual significance. In using it biolog- 

 ically, he differs widely from Osbom and 

 others who have made use of the term in a 

 pathological sense and in connection with dis- 

 ease as one of the factors in the extinction of 

 animals of the past and present. Von 

 Hansemann uses the term to indicate an ab- 

 normal or unusual increase of numbers of a 

 race or species of animals; he would not speak 

 of an epidemic of typhoid fever but would 

 describe such a wide-spread illness as due to an 

 epidemic of Bacillus typhosus. Great collec- 

 tions of fossils of one type in one geologic bed 

 similarly would be " epidemics." The reason 

 for such epidemics might be unusual abun- 

 dance of food or unusual absence of adverse 

 environmental conditions, such as absence of 

 enemies or, in a pathological sense, absence of 

 protective agents on the part of the host. 

 Such epidemics, he argues (p. 459), would be 

 another means of increasing varieties and 

 species through variation, since increase in 

 numbers means proportional increase in the 

 number of variants. 



The limits of a review do not permit of an 

 enumeration of the hundreds of other inter- 

 esting points that are brought out with de- 

 lightful clearness and fairness of presentation. 

 Many of his conclusions are, indeed, open to 

 question, especially such as result from a too 

 superficial view of the problem concerned, but 

 these are due more to ignorance of the great 

 mass of facts involved than to faulty logic. 

 Taken as a whole the book is full of valuable 

 suggestions and is an undoubted contribution 

 to the philosophy of evolution, and as such 

 will be gratefully received. 



Gary N. Calkiks 



Columbia UNi\'ERSiT'r 



Cave Vertehrates of America — A Study of 

 Degenerative Evolution. By Carl H. 

 EiGENMAN>f, Professor of Zoology, Indiana 

 University. 241 pages, 31 full-page plates 

 and Y2 text figures. Carnegie Institution of 

 Wa.shington. June, 1909. 



